J. W. Finkelstein

Ontogeny of luteinizing hormone and testosterone secretion

Abstract Plasma luteinizing hormone (LH) and testosterone (T) were measured by radioimmunoassay in 9 pubertal boys and 9 sexually mature adult men at 20 min intervals for 24 h. Polygraphic monitoring of sleep was also carried out to precisely identify sleep onset, wakefulness and specific sleep stages. In all 9 pubertal boys, plasma LH showed the characteristic augmentation of secretion synchronous with sleep. This increased LH secretory activity was effective in stimulating increased T secretion during sleep that resulted in uniformly higher mean T concentrations during sleep compared with waking. Plasma LH and T were also measured in 3 of these pubertal boys during acute inversion of the sleep wake cycle. The results showed that plasma LH and T were now augmented during the reversed daytime sleep period; the mean LH and T concentrations were significantly higher than during nocturnal waking. Measurement of LH and T in the 9 adult men showed episodic secretion of both hormones during waking and sleep periods with no consistent augmentation of either hormone during sleep.

24 HOUR PATTERNS OF INSULIN & GLUCOSE DURING TOTAL PARENTERAL NUTRITION

The concentration of glucose(G) and insulin(I) was measured every 20 rain for 24 hrs in 3 pts receiving only 18% glucose and 3.3% casein hydrolysate in order to evaluate the G & I response to total parenteral nutrition. Pt 1 received 4L by gravity drip. G was 16-158mg% and I was 0-372μU/ml. Peaks of G and I occurred whenever a new bottle of infusate was started. In pt 2 who received 5L, G was 31-210, I:0-216 and rate of flow 100-240ml/hr. Peaks of G and I corresponded to peaks of the rate of flow. In pt 2 5L of 10% glucose alone was later administered using a pump. Flow was 140-180ml/hr, G:49-93 and I:0-25. Pt 3 received 3L during a 12 hr gravity drip and a 12 hr pumped period. During the gravity drip, flow was 30-180ml/hr, G:50-123 and I:0-78. During the pumped period flow was 120ml/hr,G:66-101 and I:0-24. Urinary excretion of G was < 2% of the amount infused in all pts. The main factor controlling the conc. of G and I seems to be the rate of flow. During gravity drips marked changes in flow rate cause parallel marked changes in G and I which were eliminated during pumped periods. When the conc. of G is held relatively constant, little I is secreted, and complete utilization of nutrients takes place. These data suggest that constant infusion of hypertonic fluids will minimize fluctuations in G and I and prevent both hyperand hypoglycemia.

24 hour cortisol profiles demonstrate exaggerated nocturnal rise in diabetic children

24 hour cortisol profiles demonstrate exaggerated nocturnal rise in diabetic children.To identify altered patterns of cortisol (F) secretion and metabolism in diabetic (D) children, plasma F was measured every 20 min. for 24h in 12 normal (NL) and 11 insulin dependent,non-ketotic Ds on a single daily insulin dose.The diurnal pattern of secretion was identical. The mean 24h plasma F was similar in both groups (NL = 5.4±1.6, D=6.6±2.0 μg%; mean ±SD): but significantly elevated in the Ds between 5 a.m. and 9:20 a.m., the main secretory period of the day in both groups (NL = 8.1±1.8, D-12.2±3.2 μg%; mean ±SD, p<.001). Peak F averaged 15.5±3.8 in the NLs vs. 19.6±4.1 μg% in the Ds (mean ±SD; p<.02). 24h urinary excretion of 170HCS, free cortisol (FF), and 6B-hydroxycortisol (6βOHF) measured in 11 NLs and 19 Ds showed increased excretion of FF and 6βOHF, but not of 170HCSs in the Ds.These results demonstrate an exaggerated nocturnal rise in plasma F in D children not reflected by increased 170HCS excretion, but evidenced by elevated urinary FF and 6βOHF, more sensitive tests for hypercortisolemia. These abnormalities might be corrected by twice daily insulin therapy to improve nocturnal insulinization. Supported in part by The Gerald Sprayragen Foundation.

ONTOGENY OF LUTEINIZING HORMONE AND TESTOSTERONE SECRETION

Plasma luteinizing hormone (LH) and testosterone (T) were measured by radioimmunoassay in 9 pubertal boys and 9 sexually mature adult men at 20 min intervals for 24 h. Polygraphic monitoring of sleep was also carried out to precisely identify sleep onset, wakefulness and specific sleep stages. In all 9 pubertal boys, plasma LH showed the characteristic augmentation of secretion synchronous with sleep. This increased LH secretory activity was effective in stimulating increased T secretion during sleep that resulted in uniformly higher mean T concentrations during sleep compared with waking. Plasma LH and T were also measured in 3 of these pubertal boys during acute inversion of the sleep wake cycle. The results showed that plasma LH and T were now augmented during the reversed daytime sleep period; the mean LH and T concentrations were significantly higher than during nocturnal waking. Measurement of LH and T in the 9 adult men showed episodic secretion of both hormones during waking and sleep periods with no consistent augmentation of either hormone during sleep.