Gregory Duckett

Effects of short-term growth hormone therapy in rats undergoing 75% small intestinal resection.

Thirty 250-g male rats underwent 75% small intestinal resection and received s.c. injections of water [short gut (SG)—control], human growth hormone (hGH) at 0.1 mg/kg/dose [SG-low-dose (LD) GH], or hGH at 1.0 mg/kg/dose [SG-high-dose (HD) GH] every other day for 28 days. Ten additional rats underwent sham operation and received water injections (sham control). After 28 days, SG-control and SG-LDGH rats weighed significantly less than the sham control group; the mean weight of the SG-HDGH group was not different from other groups. Weight per centimeter of the distal ileum was greater in all SG groups compared to the sham control group, and was greater in the SG-HDGH than in the SG-control group. Mean mucosal height of the distal ileum was greater in both SG groups receiving GH than in sham controls. No differences in ileal mucosal DNA content or ileal insulin-like growth factor-1 (IGF-1) content were identified between groups. Mucosal sucrase activity was not increased in hGH-treated rats. Serum calcium and phosphorus concentrations were higher in SG-HDGH rats than in SG-control animals. HDGH increased body weight, distal ileal weight/cm, and mucosal height in rats undergoing 75% small bowel resection. A trend toward normalization of serum calcium, phosphorus, and plasma IGF-1 concentrations was also observed. Further longer-term studies are indicated to learn if GH has a beneficial effect upon gut growth and function in the SG syndrome.

Hypothalamic-pituitary function in the fetal alcohol syndrome

complementemic nephritis distinct from immunoglobulins and activating the alternate pathway of complement, J Exp Med 139:1249, 1974. 6. Warren MP, and Vande Wiele RL: Clinical and metabolic features of anorexia nervosa, Am J Obstet Gynecol 117:435, 1973. 7. Silverman JA: Anorexia nervosa. Clinical observations in a successful treatment plan, J PEDIATR 84:68, 1974. 8. Chandra RK: Immunocompetence in undernutrition, J PEDIATR 81:1194, 1972. 9. Smythe PM, Schonland M, Brereton-Stiles GG, Coovadia HM, Grace H J, Loening WEK, Mafoyane A, Parent MA, and Vos GH: Thymolymphatic deficiency and depression of cell-mediated immunity in protein-calorie malnutrition, Lancet 2:939, 1971. 10. Sirisinha S, Suskind R, Edelman R, Charupatana C, and Olson RE: Complement and C3 practivator levels in children with protein-calorie malnutrition and effect of dietary treatment, Lancet 1:1016, 1973. 11. Clark PA, Frank MM, and Kimball MR: Generation of chemotactic factors in guinea pig serum via activation of the classical and alternate complement pathways, Clin Immunol Immunopathol 1:414, 1973. 12. Winkelstein JA: Opsonins. Their function, identity, and clinical significance, J PEDIATR 82:747, 1973.

Effect of Short-Term Castration and Starvation upon Hypothalamic Content of Luteinizing Hormone-Releasing Hormone in Adult Male Rats

Summary A sensitive and specific radio-immunoassay for hypothalamic LH-RH has been described. Within 7 days after castration there is a significant decline in hypothalamic content of LH-RH in adult male rats. Total starvation for 7 days does not affect hypothalamic content of LH-RH in either intact or castrated rats. The authors thank the Hormone Distribution Officer, NIAMDD, for reagents for the radioimmuno-assay of rat LH and rat FSH. They also thank Mrs. E. Morris for secretarial assistance.

Effects of drug and alcohol abuse upon pituitary-testicular function in adolescent males

To assess the effects of drug and alcohol abuse (DAA) on the physical changes and hormones of puberty in adolescents, 26 males (13 5/12-22 years) enrolled in a drug rehabilitation program were examined. In 22 subjects four timed blood samples were obtained sequentially at 15 minute intervals for measurement of serum concentrations of testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH) and dehydroepiandrosterone sulfate (DHAS). The mean duration of DAA was 3.7 years, with marijuana and alcohol being the most frequently abused substances. The study subjects were compared to a matched control group of non-substance-abusing teenagers. All heights and weights of the DAA subjects fell within two standard deviations of the mean on the Tanner Growth Charts and no statically significant differences in the Tanner stages of sexual maturation were found between the DAA and control groups. The mean (+/- SD) testosterone level of the DAA group (221 +/- 109 ng/dl) was less than half that of the control group (477 +/- 193 ng/dl, p less than 0.001). Mean LH concentration in the DAA group (3.9 +/- 3.0 mIU/ml) was significantly less than that of the control group (10 +/- 4.9 mIU/ml, p less than 0.01). In both the DAA and control populations there was a significant (p less than 0.01) correlation between serum concentrations of LH and testosterone. The mean FSH level of the DAA group (3.3 +/- 1.1 mIU/ml) was significantly less (p less than 0.02) than that of the control group (4.7 +/- 1.9 mIU/ml). To assess the effects of treatment, six boys underwent repeat blood sampling 7-12 months after drug and alcohol withdrawal.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Synthetic Luteinizing Hormone-Releasing Hormone in Newborn Rats

Summary Administration of synthetic LH-RH to male and female rats on the first day of life reduced pituitary content of FSH and LH and increased serum concentrations of LH. The authors express their appreciation to the Hormone Distribution Officer, NIAMDD, for the generous supply of reagents for the radioimmunoassays of LH and FSH, and to Mrs. Eileen Morris for competent secretarial assistance.

Further studies of the effects of intravenous infusion or intramuscular injection of gonadotropin-releasing hormone during childhood and adolescence

To provide data on the readily releasable pools of pituitary gonadotropins and to compare routes of administration, gonadotropin-releasing hormone (Gn-RH, 100 micrograms) was administered to 135 endocrinologically normal children and adolescents by continuous intravenous 3-hour infusion or by acute intramuscular injection. The Gn-RH infusion resulted in a significant four- and sevenfold increase in serum luteinizing hormone (LH) values in prepubertal subjects and pubertal males, respectively. A 14-fold increment, biphasic in appearance, occurred in pubertal females. Gn-RH-induced serum follicle-stimulating hormone (FSH) increases were greater in females than in males. Following intramuscular injection of Gn-RH, a monophasic increment of serum LH and FSH occurred. LH rises were greater in pubertal than in prepubertal children and greater in females than in males. FSH increments were greater in females than in males, prepubertal being slightly greater than pubertal. Urinary gonadotropin excretion mirrored the changes in the serum samples. These results in the largest reported group of normal children generally confirm those of previous reports except for the greater Gn-RH-evoked releasable LH in pubertal females than in males.

Effect of Clonidine Upon Anterior Pituitary Function and Plasma Catecholamine Concentrations in Short Children and Adolescents

The effects of the alpha-adrenergic agonist Clonidine (0.15 mg/m p.o.) upon serum concentrations of growth hormone (GH), Cortisol and prolactin (PRL) were determined in 50 children and adolescents with short stature in order to determine the efficacy of this agent in the evaluation of anterior pituitary function. Two groups of short children were studied: Group I — children with constitutional delay in growth and sexual development or genetic short stature; Group II — children with GH deficiency as defined by subnormal GH secretory responses to insulin hypoglycemia, L-dopa and/or arginine. The peak GH secretory response to Clonidine (22.5 ± 2.1 ng/mL, mean ± SEM) in 28 non-GH-deficient short subjects (Group I) was greater than those recorded after sequential insulin-L-dopa (12.6 ± 1 . 0 ng/mL) or insulin-arginine (15.5 ± 2.2 ng/mL) administration. GH concentrations did not significantly increase after any provocative agent in 22 GH-deficient subjects (Group II). Mean Cortisol concentrations in Group I declined from 13.8 ± 1.0 to 6.0 ± 0.7 ug/dL at 90 minutes (p < 0.01) and returned nearly to basal levels by 180 minutes after Clonidine ingestion. Mean Cortisol concentrations in Group II declined from 11.3 ± 1.4 to 5.9 ± 0.9 ug/dL at 90 minutes (p < 0.05) and also returned to basal levels by 180 minutes. Mean basal PRL levels declined significantly in Group I (11.8 ± 1.7 to 6.7 ±1.0 ng/mL; ρ < 0.01) by 60 minutes and returned to

PARATHYROID HORMONE REGULATION IN CHILDREN WITH CHRONIC RENAL DISEASE

The regulation of immunoreactive parathyroid hormone (IPTH) levels has been examined in three groups of children. I. In 5 children with renal insufficiency, 4 had renal osteodystrophy. Calcium infusions of 4 mg/kg/hour for 4 hours reduced IPTH to less than 40% of the elevated baseline levels. Following glucagon administration, which lowered serum calcium in 4 of 5 children, IPTH levels in 3 increased transiently by 20%. These changes indicated that these children had suppressible parathyroid function (non-autonomous). II. In 4 children being hemodialyzed against a bath with Ca++ concentration ranging from 7-8 mg/dl,the (Ca++) of the venous line progressively rose. It also always exceeded that of the arterial line, indicating net calcium absorption by the body. IPTH levels fell as serum(Ca++) increased. These changes indicate that the use of a high(Ca++) in the dialysis bath is useful in suppressing parathyroid hyperactivity. III. Changes in (Ca++), (PO−4) and IPTH were determined following 5 episodes in 4 children of acute transplant rejection being treated by 15 mg/kg of IV prednisolone.(Ca++) fell in all 5. Changes in IPTH levels were not consistent and failed to parallel changes in (Ca++). These changes suggest that high doses of steroids may acutely affect serum (Ca++), independently of their effect on the parathyroid glands.Supported by NIH grants RR-5624, RR-75 and HD-04840.

Validation of a Rapid Assay for Determination of Leptin Binding in Serum|[dagger]| 417

We have previously reported the measurement of leptin binding protein(s) in serum by subjecting incubates of serum and 125I- leptin, neat and with excess cold leptin, to filtration on Ultragel ACA 44 columns (BBRC233:818-822, 1997). We have now developed a more rapid “spun-column” method. With the plunger removed, a tuberculin syringe suspended in a 15 mL centrifuge tube was packed with 1.0 mL of Sephacryl S-200 HR resin by centrifugation at 860 × gav for 3 min at 40C. After packing, the spun-column was equilibrated against 0.05 M Tris-HCl buffer, pH 7.5, 0.15 M NaCl by three successive washes of 100 μL of buffer and centrifugation. To collect the sample eluate, a 1.5 mL microcentrifuge tube was placed at the bottom of the 15 mL centrifuge tube into which the spun-column was inserted with the syringe tip inside the microcentrifuge tube. 125I-Leptin was purchased from Linco Inc.(St. Charles, MO) and further purified by filtration on an Ultragel ACA 34 and 44 column. Serum (150μL) was incubated with 150μL purified125 I-leptin (approximately 10-20,000 cpm) and 100μL of buffer, neat or with 100 ng of cold leptin for 2 hr at 40C. An aliquot (300μL) of the incubate was then assayed as previously described using the Ultragel ACA 44 column. At the same time, an aliquot (100μL) of the incubate was loaded on a spun-column and centrifuged. After centrifugation, the microcentrifuge tube containing the spun-column eluate was removed and counted to determine “bound” counts while the resin was blown from the spun-column into a test tube with an air jet and counted to assess “unbound” leptin. Total binding was determined by dividing “bound” by total counts. Percent specific binding was calculated by subtracting percent total binding determined in the presence of excess competitor leptin from percent total binding in the absence of competitor. Serum was collected from 27 patients and assayed simultaneously by both methods. Specific binding was higher by the Ultragel method (mean=18.3% vs 14.0%, p<0.02) and the values were highly correlative (r=.89,p<.0001). Specific binding in both methods correlated inversely with serum leptin levels (Ultragel, r=-0.79, p<0.0001; and spun-column, r=-0.63, p<0.001). We conclude that the “spun-column” method offers a simple, rapid, and quantitative method for determination of leptin binding in serum.

493 EFFECTS OF HUMAN PANCREATIC GROWTH HORMONE RELEASING HORMONE (HPGRH) ON GROWTH HORMONE (GH) SECRETION IN PREGNANT AND FETAL RATS

Pregnant Holtzman rats were studied at 19 and 20 days gestation. Animals were anesthetized at -30 min with pentobarbitol 60 mg/kg IP. 5 ug HPGRH 1–44 or normal saline was administered IV at 0 min. Blood for maternal GH measurement was obtained via cardiac puncture at 0 min and following decapitation at 11 min. Fetuses were removed by C-section between 7 and 11 min and cardiac blood from littermates pooled for a single fetal GH determination. *x±SD **ng/mlMean maternal GH levels rose significantly (p < 0.005) in animals receiving HPGRH and were unchanged in those receiving saline. Mean fetal GH levels were significantly greater (p < 0.005) at 20 vs 19 days gestation. There were no significant differences between mean fetal GH concentrations of mothers receiving HPGRH and those receiving saline. HPGRH increases GH concentrations in the pregnant rat. HPGRH administration to the pregnant rat during late gestation does not increase GH concentrations in the fetus suggesting either that HPGRH does not cross the rat placenta or that the fetal rat pituitary is insensitive to HPGRH at this dosage.