Burton L. Baker

Increase in Glyceride Content of Brown Fat by Treatment with Adrenocorticotropin.

Summary Treatment of intact or castrated rats with ACTH caused an increase in the glyceride content of brown adipose tissue. Treatment of hypophysectomized rats with 3 times the dose used above failed to maintain the fat content of the interscapular gland at a normal level.

Immunocytochemical Analysis of Cells in the Pars tuberalis of the Rat Hypophysis with Antisera to Hormones of the Pars distalis

SummaryThe objective was to acquire evidence regarding the secretory capacity of cells in the pars tuberalis of the rat pituitary by the application of immunocytochemical staining. For this purpose the conjugated antibody and immunoglobulin-enzyme bridge techniques were utilized with antisera to the following hormones of the pars distalis: human somatotropin, human thyrotropin, human β-melanotropin, ovine luteinizing hormone (LH), porcine β17–39-corticotropin, and β1–24-corticotropin. Only LH-containing cells were demonstrated. They were exceedingly rare in the cephalic pars tuberalis beneath the median eminence. The frequency of LH-cells was greater in the pars tuberalis associated with the infundibulum and increased distally. LH-cells were most common ventrolateral to the infundibular stem and occurred singly and in clusters. These results indicate that following hypophysectomy the portion of the pars tuberalis that remains in situ has the capacity to secrete only LH of all the pars distalis hormones.

THE RELATIONSHIP OF THE ADRENAL, THYROID, AND PITUITARY GLANDS TO THE GROWTH OF HAIR

Since hair appears to be one of the most rapidly growing structures of the body, one might expect that it would serve as a sensitive indicator of the modifying action of hormones on general body growth. In this sense, alterations in the rate of growth of hair might be regarded solely as a reflection of any general metabolic changes induced by the hormones. On the contrary, it is possible that hormones modify the growth of hair in a way that is different from the effects which they elicit elsewhere in the body. In other words, is the response of hair to the action of these humoral agents so unique that the piliary system should be regarded as a special target organ? In the following presentation, we shall seek to analyze the effects of hormones on the piliary system in the light of these two alternatives. The r61e played by the secretions of the adrenal, thyroid, and pituitary glands in the regulation of the growth of hair has been investigated chiefly in two forms, the rat and man. Therefore, information which has been derived from study of the rat will be emphasized and an attempt made to correlate these findings with the more limited information which is available concerning the relationship of these glands to hair in man.

Cellular composition of the human pituitary pars tuberalis as revealed by immunocytochemistry

SummaryAn attempt was made to determine if any of the specialized secretory cell types common to the pars distalis also occur in the pars tuberalis of the human hypophysis. Available for study were 18 specimens of the inferior pars tuberalis, which partially surrounds the infundibular stem, and 3 specimens of the superior pars tuberalis that is attached to the median eminence. Antisera to human somatotropin, mammotropin, chorionic gonadotropin, follicle-stimulating hormone, FSH β, luteinizing hormone, LH β, thyrotropin, TSH β, as well as to β1–24-corticotropin, porcine β17–39-corticotropin, and ovine LH were used with the Sternberger peroxidase-antiperoxidase immunocytochemical procedure to identify the probable cells of origin for these hormones.The evidence indicated that gonadotropic cells constitute the major portion of the parenchymal cell population in the pars tuberalis. They occurred throughout all of the pars tuberalis and were usually arranged in clusters. Somatotropic, mammotropic, corticotropic, and thyrotropic cells were rare and not found in all specimens. When present, they often formed a common group suggesting that their occurrence in the pars tuberalis resulted from displacement of primordial tissue of the pars distalis during embryogenesis.

Circadian Periodicity in the Concentration of Prolactin in the Rat Hypophysis

Prolactin activity in the hypophyses of rats maintained under standardized conditions was assayed in pigeons. The concentration of prolactin in the gland exhibited a circadian rhythm.

The Influence of Hypophysectomy on the Stores of Somatostatin in the Hypothalamus and Pituitary Stem

Summary Twenty-eight to 133 days after hypophysectomy of the rat, somatostatin as revealed immunocytochemically was depleted from all segments of the median eminence and from the proximal part of the infundibular stem. A consistent change in the store of somatostatin in the OVLT could not be demonstrated.

Effect of Treatment with AGTH or Cortisone on Anatomy of the Brain.

Summary Administration of ACTH caused chromatolysis in the cells of the paraventricular hypothalamic nucleus. Cortisone affected this nucleus but induced more widespread chromatolysis and vacuolation of thalamic and hypothalamic nerve cells.

Histochemical variations in the metrial gland of the rat during pregnancy and lactation.

Summary During pregnancy and lactation the metrial gland is marked successively by the prominence of (1) ribonucleic acid, (2) eoinophilic granules and glycogen, and (3) lipids. These appear to be related, respectively, to growth and secretion, nutrition for the embryo and steroid metabolism.

Effect of treatment with growth hormone on somatostatin in the median eminence of hypophysectomized rats.

Summary Treatment of rats with growth hormone partially prevented depletion of somatostatin from the median eminence when therapy was begun immediately following hypophysectomy, and partially restored somatostatin when treatment was initiated after a prolonged posthypophysec-tomy interval. These observations suggest that growth hormone tends to increase the store of somatostatin in the median eminence.

Histology and Regenerative Capacity of Liver Following Multiple Partial Hepatectomies.

Summary The capacity of liver to regenerate was maintained in rats which were subjected to partial hepatectomy 12 times within a period of one year. At the end of the experiment, only minor cytological changes were observed in the regenerated liver and there was no neoplasia.