Follicular Steroidogenesis: Effect of Reproductive Condition

Bahr, Janice M.; Gardner, Rod; Schenck, P. E.; Shahabi, Nahid

doi:10.1095/biolreprod22.4.817

Cited by 40 publications

(11 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Concentrations of progesterone were determined by radioimmunoassay as previously described (Bahr et al, 1980;Wiseman et al, 1982). The progesterone antibody (obtained from Dr O. D. Sherwood (GS 253)) was generated against progesterone-1 lß-hemisuccinate: BSA and cross-reacts 22% with 11 ß-hydroxyprogesterone.…”

Section: Progesterone Radioimmunoassaymentioning

confidence: 99%

Adenylate cyclase activity of the corpus luteum during the oestrous cycle of the pig

Ritzhaupt¹,

Nowak²,

Calvo³

et al. 1986

Reproduction

View full text Add to dashboard Cite

Basal adenylate cyclase values for corpora lutea (CL) removed from cyclic gilts on Days 3, 8, 13 and 18 were 178 +/- 61, 450 +/- 46, 220 +/- 25 and 208 +/- 18 pmol cAMP formed/min/mg protein, respectively. Basal activity was significantly elevated on Day 8 (P less than 0.001). LH-stimulatable adenylate cyclase values for CL from Days 3, 8, 13 and 18 were 242 +/- 83, 598 +/- 84, 261 +/- 27 and 205 +/- 17 pmol cAMP formed/min/mg protein respectively. Serum progesterone concentrations of 12 gilts bled every 2 days through one complete oestrous cycle ranged from 1.1 to 26.9 ng/ml with highest values between Days 8 and 12. The decline in serum progesterone concentrations was coincident with the decrease in basal adenylate cyclase activity. There was no LH-stimulatable adenylate cyclase activity present in the CL at the specific times of the oestrous cycle examined. We conclude that progesterone secretion by the pig CL is apparently dependent on basal activity of adenylate cyclase.

show abstract

Section: Progesterone Radioimmunoassaymentioning

confidence: 99%

Adenylate cyclase activity of the corpus luteum during the oestrous cycle of the pig

Ritzhaupt¹,

Nowak²,

Calvo³

et al. 1986

Reproduction

View full text Add to dashboard Cite

show abstract

“…Progesterone, or a metabolite of progesterone, is involved in the preovulatory decline in oestradiol synthesis in the hamster (Saidapur & Greenwald, 1979b), whilst in preparations of testicular tissue of the rat progesterone inhibits the C17-20 lyase enzyme (Inano, Nakano, Shikita & Tamaoki, 1967;Mahajan & Samuels, 1975). Also, the preincubation of perifused rabbit follicles in medium containing progesterone decreased the secretion of oestradiol (Bahr, Gardner, Schenk & Shahabi, 1980).…”

Section: Discussionmentioning

confidence: 99%

Effect of LH on steroidogenesis by hamster follicles isolated at defined stages of development

Matson¹,

Gledhill²,

Collins³

1984

Reproduction

View full text Add to dashboard Cite

Multiple follicular growth was stimulated in groups of immature female hamsters by the administration of PMSG. The ovaries were removed 72-78 or 96-102 h later. The animals at 96-102 h were subdivided according to whether the concentration of plasma progesterone was within the range of the concentrations found at the previous period (0.45-13.18 nmol/l; Group I) or above (Group II). Thecal and granulosa cells from batches of isolated follicles (591-740 micron) were cultured together in the presence or absence of LH and the products of steroidogenesis were measured in the culture fluid. The results showed that there was a significant increase in the production of progesterone and 17 alpha-hydroxyprogesterone in follicles from Groups I and II at 96-102 h. In the presence of LH there was a significant increase in the yield of progesterone and 17 alpha-hydroxyprogesterone over the control values at all time periods. There were, however, reductions in the yields of 17 alpha-hydroxyprogesterone and androstenedione in the presence of LH at 96-102 h compared with 72-78 h and in Group II compared with Group I, although the concentrations of 17 alpha-hydroxyprogesterone were approximately 40-fold those of androstenedione. In addition, the production of oestradiol decreased significantly in follicles from both groups at 96-102 h and was reduced further in the presence of LH. It is concluded that the major rate-limiting step of steroidogenesis in hamster follicles undergoing the oestrogen-progestagen shift involves the side-chain cleavage of 17 alpha-hydroxyprogesterone.

show abstract

“…Samples were analyzed for P 4 without extraction by radioimmunoassay as validated previously in our laboratory [10]. Tissue samples were sonicated and analyzed for protein content in the Lowry assay [11].…”

Section: Assaysmentioning

confidence: 99%

Identification and Preliminary Characterization of Luteotropic Activity in the Rabbit Placenta1

Marcinkiewicz

Bahr

1993

Biology of Reproduction

View full text Add to dashboard Cite

The corpus luteum of the rabbit requires estradiol (E2) and the conceptus to maintain progesterone (P4) during the second half of pregnancy. The factor produced by the fetal placenta that is responsible for maintaining P4 production has not yet been identified. Therefore, the goal of these experiments was to determine whether the rabbit placenta contained luteotropic activity and to begin preliminary characterization of this factor. A bioassay system utilizing corpora lutea explants incubated with placental extracts and other treatments was developed and validated. Neither pooled placental extracts (200 micrograms) nor E2 alone affected P4 production (p > 0.05). However, the combination of placental extracts plus E2 significantly stimulated P4 production approximately 1.5-fold (p < 0.05). Skeletal muscle (200 micrograms) + E2 also had no effect on P4 production, indicating that the effect of placental extracts was tissue-specific. Carboxymethyl-cellulose ion-exchange chromatography of placental extracts yielded four separate fractions, which were examined individually at three doses for activity in the bioassay system. The first and most acidic fraction (Fraction 1) significantly stimulated P4 production at 10 and 100 micrograms when incubated in combination with E2 (p < 0.05). Both heat and trypsin treatment abolished the ability of placental Fraction 1 to stimulate P4 production in the presence of E2. Size fractionation of Fraction 1 using dialysis membranes with 3500, 6000-8000, and 12,000-14,000 molecular weight cutoff points had no effect on bioactivity of Fraction 1. These results indicate that the rabbit placenta contains a potential luteotropin with the characteristics of an acidic, heat-sensitive protein greater than 12,000-14,000 in molecular weight.

show abstract

Follicular Steroidogenesis: Effect of Reproductive Condition

Cited by 40 publications

References 26 publications

Adenylate cyclase activity of the corpus luteum during the oestrous cycle of the pig

Adenylate cyclase activity of the corpus luteum during the oestrous cycle of the pig

Effect of LH on steroidogenesis by hamster follicles isolated at defined stages of development

Identification and Preliminary Characterization of Luteotropic Activity in the Rabbit Placenta1

Contact Info

Product

Resources

About