Isolation of estradiol-17-beta from hen's urine and its characterization as the crystalline 3-methyl ether.
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Animals↗
Biomedical subjects
R S Mathur
Publications and source records attributed to R S Mathur.
Vasoactive intestinal polypeptide stimulates nonovarian progesterone secretion in rabbits.
Recent experiments conducted in this laboratory have shown that intravenous infusions of vasoactive intestinal polypeptide (VIP) induced significant increases in plasma progesterone (P) in female rabbits. The purpose of this study was to determine the organ source of this P and to clarify the mechanisms by which it is induced. Intravenous infusions of VIP (37.5, 75, and 150 pmol/kg per min for 60 min) produced acute dose-dependent increases in plasma P in intact estrous rabbits. In ovariectomized (OVX) animals, VIP infusion (75 pmol/kg per min) produced a P increase of the same magnitude. In animals both OVX and adrenalectomized (ADX), this VIP effect was eliminated. The only significant change noted in luteotropic hormone (LH) or follicle stimulating hormone (FSH) was a decrease in FSH immediately following VIP infusion (150 pmol/kg). VIP infusion significantly increased plasma cortisol in intact and OVX animals, but not in OVX/ADX animals. It is concluded that VIP primarily stimulates the adrenal component of P secretion in the rabbit, via mechanisms independent of LH or FSH.
Adrenalectomy↗
Effects of atrial natriuretic peptide on rat ovarian granulosa cell steroidogenesis in vitro.
PROBLEM: The localization and biological effects of atrial natriuretic peptide (ANP) are not limited to cardiac tissue but extend to a number of extra-atrial tissues and organs, including the ovary. The objective of the present study was to determine the effects of ANP on granulosa cell steroidogenesis. Hence, the direct effects of ANP on the production of progesterone, 20 alpha-hydroxpregn-4-en-3-one (20 alpha-OH-P), and estrogen by undifferentiated and differentiated rat ovarian granulosa cells were examined in vitro. METHOD: Undifferentiated granulosa cells obtained from the ovaries of diethylstilbestrol-primed, immature rats were treated with increasing doses (10(-12) to 10(-6) M) of rANP for 48 h. RESULTS: ANP evoked a two- and threefold increase in progesterone and 20 alpha-OH-P production relative to untreated controls, respectively. Increasing doses of ANP in combination with porcine FSH (125 ng/well) resulted in a biphasic response in progesterone production above FSH-treated controls. Specifically, a maximal inhibition of 35% in progesterone production was achieved at 10(-9) M ANP, followed by a stimulation to levels comparable with FSH-stimulated controls at higher doses examined. Increasing doses of ANP evoked a twofold increase in FSH-stimulated 20 alpha-OH-P production over respective controls. Following pretreatment of granulosa cells with FSH for 48 h to evoke differentiation, ANP caused a significant dose-dependent inhibition in basal progesterone production that resulted in a 76% suppression at the highest dose examined. In contrast, ANP evoked a 2.8-fold increase in 20 alpha-OH-P production when compared with controls. Finally, in FSH-stimulated differentiated granulosa cells, ANP evoked a threefold increase in progesterone production and a 65% inhibition in 20 alpha-OH-P production. ANP exerted no significant effects on estrogen production by either undifferentiated or differentiated granulosa cells in the presence or absence of FSH. CONCLUSIONS: These data demonstrate that ANP can modulate directly progestin steroidogenesis in both undifferentiated and differentiated rat ovarian granulosa cells in vitro and, therefore, may play an important role in granulosa cell differentiation and follicular maturation.
20-alpha-Dihydroprogesterone↗
Effects of nicotine on sperm attachment and penetration of zona-free hamster eggs.
A previous study from this laboratory showed that nicotine in vitro has deleterious effects on sperm motion characteristics. This study was conducted to evaluate the effects of nicotine on the ability of human spermatozoa to attach and penetrate zona-free hamster eggs. Spermatozoa from fertile donors, washed free of seminal plasma, were incubated with medium (control) and 0.1, 1, 5, and 10 mM concentrations of nicotine (concentrations estimated to approximate residual concentrations of nicotine in the testes of heavy smokers) for 18 h at 37 degrees C in a humid 5% carbon dioxide incubator. The sperm preparations were then mixed with enzymatically denuded hamster eggs and incubated for 3 h at 37 degrees C. The oocytes were examined by phase-contrast microscopy to enumerate the rates of sperm attachment and penetration. The data were analyzed by a paired t test and repeated measures analysis of variance using the arcsine transformation of the percentages. The percentages of eggs with attached spermatozoa significantly declined in a dose-dependent manner, the highest inhibition being at 10 mM (F = 24). The rate of sperm penetration was even more significantly decreased with the increase in nicotine concentrations in the following order: 10 mM (F = 56) > 5 mM (F = 30) > 1 mM (F = 44) > 0.1 mM (F = 12). Nicotine concentrations of 0.1 mM and above negatively affected sperm penetration of zona-free hamster eggs.
Adult↗
Ultrastructural study of epidermal Langherhans cells in leprosy.
ATPase staining and ultrastructural study of skin biopsies from six patients of leprosy (2TT, 4LL) and three normal subjects was carried out to study Langherhans Cells (LC). ATPase staining showed normal counts of LCs in tuberculoid patients, while significant reduction was observed in lepromatous cases. Electron microscopy revealed morphological changes in LL cases in the form of dense matrix and indistinct cristae of mitochondria; decreased number of lysosomes and rough endoplasmic reticulum; and numerous vacuoles in cytoplasm. TT cases showed normal morphology. Possible role of Langerhans Cells in pathogenesis of leprosy is discussed.
Humans↗