Follicle-stimulating hormone receptor-mediated uptake of sup 45 Ca sup 2+ by proteoliposomes and cultured rat sertoli cells: Evidence for involvement of voltage-activated and voltage-independent calcium channels

Journal Article · Fri Dec 01 00:00:00 EST 1989 · Endocrinology; (USA)

DOI:https://doi.org/10.1210/endo-125-6-3029· OSTI ID:5037963

Grasso, P; Reichert, Jr, L E ^[1]

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1. Albany Medical College, NY (USA)

We have previously reported incorporation into liposomes of Triton X-100-solubilized FSH receptor-G-protein complexes derived from purified bovine calf testis membranes. In the present study we have used this model system to show that FSH induces flux of 45Ca2+ into such proteoliposomes in a hormone-specific concentration-dependent manner. FSH, inactivated by boiling, had no stimulatory effect on 45Ca2+ flux, nor did isolated alpha- or beta-subunits of FSH. Addition of GTP (or its analogs 5'-guanylylimidodiphosphate and guanosine-5'-O-(3-thiotriphosphate)) or sodium fluoride (in the presence or absence of GTP or its analogs) failed to induce 45Ca2+ flux into proteoliposomes, suggesting that the uptake of 45Ca2+ was receptor, and not G-protein, related. Voltage-independent (ruthenium red and gadolinium chloride) and voltage-activated (methyoxyverapamil and nifedipine) calcium channel-blocking agents reduced FSH-stimulated 45Ca2+ flux into proteoliposomes to control levels. FSH also induced uptake of 45Ca2+ by cultured rat Sertoli cells. Ruthenium red and gadolinium chloride had no effect on basal levels of 45Ca2+ uptake or estradiol secretion by cultured rat Sertoli cells, nor did methoxyverapamil or nifedipine. All four calcium channel blockers, however, were able to reduce FSH-induced 45Ca2+ uptake to basal levels and FSH-stimulated conversion of androstenedione to estradiol by up to 50%, indicating an involvement of Ca2+ in FSH-stimulated steroidogenesis. Our results suggest that the well documented changes in intracellular calcium levels consequent to FSH binding may be due, at least in part, to an influx of calcium through FSH receptor-regulated calcium channels.

• OSTI ID: 5037963
• Journal Information: Endocrinology; (USA), Vol. 125:6; ISSN 0013-7227
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CALCIUM
MEMBRANE TRANSPORT
FSH
RECEPTORS
ANDROSTENEDIONE
BIOCHEMICAL REACTION KINETICS
CALCIUM 45
CALVES
CATTLE
CELL CULTURES
CELL MEMBRANES
DOSE-RESPONSE RELATIONSHIPS
ELECTROPHYSIOLOGY
ENZYME INHIBITORS
ESTRADIOL
GUANOSINE
LIPOSOMES
PORINS
TESTES
TRACER TECHNIQUES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANDROGENS
ANDROSTANES
ANIMALS
AROMATICS
AZAARENES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CALCIUM ISOTOPES
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELEMENTS
ESTRANES
ESTROGENS
EVEN-ODD NUCLEI
GONADOTROPINS
GONADS
HETEROCYCLIC COMPOUNDS
HORMONES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
KINETICS
MALE GENITALS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
METALS
NUCLEI
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOIDS
ORGANS
PEPTIDE HORMONES
PHYSIOLOGY
PITUITARY HORMONES
PROTEINS
PURINES
RADIOISOTOPES
REACTION KINETICS
RIBOSIDES
RUMINANTS
STEROID HORMONES
STEROIDS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques