Worcester Foundation for Biomedical Research

About: Worcester Foundation for Biomedical Research is a based out in . It is known for research contribution in the topics: Estrone & Estrogen. The organization has 2195 authors who have published 2646 publications receiving 115809 citations. The organization is also known as: Worcester Foundation for Experimental Biology.

Peak duration of serum melatonin and short-day responses in adult Siberian hamsters.

Abstract: Long photoperiod-housed, adult Siberian hamsters were pinealectomized and given daily subcutaneous infusions of melatonin (MEL) to determine which characteristic of the MEL secretion profile is critical for short photoperiod-induced physiological responses. Long-duration MEL infusions (10 or 12 h) given for 5 wk elicited short-day-type responses [i.e., decreased body, testes, and epididymal white adipose tissue (EPIWAT) weights, EPIWAT lipoprotein lipase activity, carcass lipid content, and serum follicle-stimulating hormone and prolactin levels]. In contrast, short- or intermediate-duration (5 or 8 h) MEL infusions or saline infusions were without effect. Long-duration MEL infusions elicited short-day-type responses independently of both the time of day when MEL was administered and of the MEL dose if the latter was greater than or equal to 6.25 ng MEL/daily infusion. The continuity of the 10-h MEL infusions was important for triggering short-day-type responses; 10-h MEL infusions interrupted at their midpoint by 2 h of no infusion were ineffective even though dose and total duration were held constant. The body and lipid mass decreases were independent of the gonads, since castrated and gonad-intact hamsters responded similarly to the daily 10-h MEL infusions. Decreased body weight resulting from long-duration MEL infusions were never accompanied by decreased food intake. We conclude that the peak nocturnal duration of MEL is the critical parameter of the MEL secretion profile for triggering short-day-induced responses in adult Siberian hamsters.

Dehydrogenase in the rat ovary. I. A histochemical study of delta-5-3-beta-and 20-alpha-hydroxysteroid dehydrogenases and enzymes of carbohydrate oxidation during the estrous cycle.

Abstract: Ovaries of 120- to 140-day-old rats were examined histochemically throughout the estrous cycle for changes in distribution and intensity of the activities of 3 carbohydratemetabolizing and 2 steroid-converting enzymes. The enzymes of carbohydrate oxidation were: lactic dehydrogenase (LD), succinic dehydrogenase (SD), and glucose-6-phosphate dehydrogenase (G6PD). 20α-Hydroxypregn-4-en-3-one and dehydroepiandrosterone were used as substrates for the study of 20α-hydroxysteroid dehydrogenase (20α-OHD) and Δ6-3β-hydroxysteroid dehydrogenase (3β-OHD) activities, respectively. Infoldings of the germinal epithelium were distinguished from the rest of the surface epithelium by a stronger activity of certain carbohydrate-metabolizing enzymes. Primary follicles, closely associated with these epithelial infoldings, exhibited identical histochemical characteristics. In the granulosa cells in some of the graafian follicles, 3β-OHD activity became demonstrable and G6PD activity increased markedly on the second day of d...

Stimulation by follicle-stimulating hormone of synthesis of lactate by Sertoli cells from rat testis.

Abstract: Sertoli cells from rats aged 16 days were cultured in defined medium for 2 days and then treated by addition of fresh medium containing various hormones (treated) or saline (control). The concentration of lactate in the medium was measured as a function of time. The production of lactate measured under these conditions was increased by addition of FSH to the medium. For NIH FSH (13 and 14), ED50 for stimulation of lactate production was approximately 0.05 micrograms/ml. Stimulation was also seen with LH and TSH (ED50, 0.8 micrograms/ml for both hormones). Reasons are given for believing that TSH may possess the inherent capacity to stimulate production of lactate in contrast to LH, which appears to act only by way of contaminating traces of FSH. Dibutyryl cAMP also stimulates lactate production by Sertoli cells. Other hormones tested, including androgens, were without effect. When production of lactate by Sertoli cells was compared with the maximal consumption by spermatids in vitro, it became apparent that Sertoli cells may provide the major source of metabolic substrate for spermatids in the form of lactate. Stimulation of lactate production by FSH was inhibited by puromycin, cycloheximide, and actinomycin D. Evidently this response requires synthesis of new protein and RNA. This effect of FSH may be important in the regulation of spermatogenesis.

Effects of prolactin (PRL) on pituitary and testicular function in mice with hereditary PRL deficiency.

Abstract: Hereditary dwarf mice (Snell dwarf, dw/dw and Ames dwarf, dfldf) are genetically prolactin-deficient and sterile. Treatment with prolactin (PRL) stimulates testicular growth and activity, and induces fertility in these animals. To elucidate the mechanism of this action of PRL, and to identify the possible physiological functions of this hormone during sexual maturation, we have examined the effects of treating male dwarf mice with PRL on plasma and pituitary levels of LH and FSH, on the concentration of testosterone (T) in testes and plasma, and on T production in response to hCG in vitro. Both Snell and Ames male dwarf mice had a significantly lower concentration of FSH in the pituitary and the peripheral plasma, and of LH in the pituitary, than did the normal adult males of the same strain. Treatment with ovine PRL, or with a PRL-producing ectopic homograft of the anterior pituitary from a normal animal, produced a significant elevation in plasma FSH levels in male dwarf mice of both strains. The same i...