Effects of gonadotropins upon the incidence and kinetics of meiotic maturation of macaque oocytes in vitro.

The specific aim of this study was to determine the effects of gonadotropins in vitro upon the incidence of and precise time interval to germinal vesicle breakdown (GVB) and extrusion of the first polar body (PB1) in oocytes from nonstimulated rhesus monkeys. Cumulus-enclod germinal vesicle (GV) stage oocytes from 10 normal, cycling rhesus monkeys in the follicular phase of the menstrual cycle were cultured with either: (1) 1.0 micrograms/ml human follicle-stimulating hormone (hFSH), (2) 10 micrograms/ml human luteinizing hormone (hLH), (3) 1.0 microgram/ml hFSH and 10 micrograms/ml hLH, or (4) no gonadotropins (controls). Oocytes (n = 234) were examined at 3-hr intervals from 0 to 21 hr and at 4-hr intervals from 24 to 52 hr for GVB and PB1. Neither the incidence of GVB (hFSH: 63.5%; hLH: 56.1%; both gonadotropins: 63.1%; no gonadotropins: 53.6%) nor extrusion of PB1 (hFSH: 41.3%; hLH: 36.4%; both gonadotropins: 36.9%; no gonadotropins; 31.9%) differed (P > 0.05) among treatments. The time to GVB was accelerated (P < 0.05) by gonadotropins (hFSH: 10.8 +/- 1.7 hr; hLH: 10.1 +/- 1.8 hr; both gonadotropins: 8.8 +/- 1.1 hr) when compared to controls (17.4 +/- 2.0 hr). However, the time interval to extrusion of PB1 did not differ (P > 0.05) among treatments (hFSH: 32.3 +/- 1.2 hr; hLH: 35.1 +/- 1.4 hr; both gonadotropins: 35.2 +/- 1.3 hr; no gonadotropins: 34.1 +/- 1.2 hr). The mean interval to extrusion of PB1 was 34.1 +/- 0.6 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromatin configurations and meiotic competence of oocytes are related to follicular diameter in nonstimulated rhesus monkeys.

Specific aims of this study were to compare relationships between size of intact antral follicles and meiotic competence, diameters, and chromatin configurations of germinal vesicle (GV) oocytes in non-gonadotropin-stimulated rhesus monkeys. Intact antral follicles were dissected from excised ovaries of nine normally cycling monkeys in the follicular phase of the menstrual cycle and of two acyclic monkeys. Follicles were classified according to diameter: I (200-450 microns), II (451-700 microns), III (701-1000 microns) and IV (> 1000 microns). Cumulus-enclosed oocytes were released from follicles and either measured (diameter) and fixed immediately or cultured for 48 h in modified CMRL medium containing 0.5 micrograms/ml ovine FSH, 10 micrograms/ml ovine LH, and 10% bovine calf serum. Following Hoechst staining, three distinct patterns of chromatin organization (GV1-3) were identified in GV oocytes according to the degree of association with the nucleolar periphery (encapsulation or "rimming"). In antral follicles > 450 microns in diameter, perinucleolar encapsulation (GV3) of oocytes before culture and meiotic maturation (metaphase II) of oocytes after culture increased (p < 0.01) with antral follicle growth in a graded fashion. While 56.3% of oocytes from large (> 1000 microns) follicles completed maturation, few (9.3%) oocytes from small (200-450 microns) follicles were competent to mature in vitro. At 0 h of culture, class IV follicles contained a greater (p < 0.01) proportion of GV3 oocytes and a smaller (p < 0.01) proportion of GV1 oocytes than classes I, II, and III follicles.(ABSTRACT TRUNCATED AT 250 WORDS)