Factors affecting the response of the female rat reproductive system to cannabinoids.

Chronic oral administration of either crude marihuana extract (CME) or delta 9-tetrahydrocannabinol (THC) to female Fischer rats for 64-72 days, at a dose approximating heavy usage by humans, reduces food intake by about 8%. Pair-feeding studies demonstrate that this decreased food intake accounts for previously described decreases in uterine and ovarian weights, which are much more affected by food restriction than is body weight. THC-treated rats lost weight initially which was not regained. Pair-fed rats gained only about one-half of the weight of the untreated control or vehicle-treated control rats over a 64-day period. Although long-term cannabinoid administration leads to tolerance and the resumption of the estrous cycle, the onset of estrus is often delayed when cannabinoid is administered 5-6 hr before the proestrus luteinizing hormone (LH) surge. Our results indicate that although chronic exposure to cannabinoids can continue to affect the rat estrous cycle, they do not have a direct effect on growth of the reproductive organs. The results reemphasize the need for adequate nutritional controls in marihuana and other toxicological research.

The effect of intragastric administration of delta 9-tetrahydrocannabinol on the growth and development of fetal mice of the A/J strain.

Pregnant A/J mice were intubated with vehicle (sesame oil:Tween 80:water) or 60, 120, or 240 mg/kg of delta 9-tetrahydrocannabinol on Days 11 and 12, 12 and 13, or 13 and 14 (vehicle and 240 mg doses only) of gestation. Mice were killed on Day 20 of gestation, and examined for number of corpora lutea and live and resorbed fetuses. Fetuses were weighed and examined for gross external and internal malformations. Each treatment group consisted of a minimum of 10 litters with about 10 pups per litter. In a few groups the effects of feed deprivation on Day 12 or of glucocorticoid administration on Days 12 and 13 (positive control) were assessed. Intubation with vehicle or delta 9-tetrahydrocannabinol, or feed deprivation did not affect number of live fetuses, incidence of resorption, fetal weights, or gross malformations other than cleft palate. Intubation of delta 9-tetrahydrocannabinol on gestational Days 12 and 13 or 13 and 14 increased the mean frequency of cleft palate formation. The increase was 2- to 2.5-fold at the 240-mg dose, being significant (p = 0.05) in the Days 12 and 13 group. Cortisone acetate and corticosterone injection induced both resorption and cleft palate formation. Other developmental or reproductive parameters were not influenced by delta 9-tetrahydrocannabinol treatment. We conclude that delta 9-tetrahydrocannabinol administered by gavage during Days 12 and 13 of gestation retards normal palatal development.

Effects of cannabinoids on function of testis and secondary sex organs in the Fischer rat.

Chronic oral treatment of young adult male Fischer rats with delta 9-tetrahydrocannabinol (THC), 1, 5 and 25 mg kg-1 day-1, or crude marihuana extract (CME), 3, 15 and 75 mg kg-1 day-1, reduced body weight gain by about 50-80% at the high CME or THC dose and was correlated with decreased food intake. When cannabinoid was administered early in the light cycle (9-11 a.m.), cauda epididymis sperm count and seminal vesicle fluid and fructose content were depressed to 50-65% at the high dosages but were not significantly different from those of pair-fed controls. Administration late in the light cycle (4-5 p.m.) depressed epididymal sperm count, seminal vesicle fluid content, and weight of testis, seminal vesicles and epididymis to 40-80% below that seen for pair-fed controls. 24 h after the last treatment, serum testosterone was unchanged in intubated control and low-dose treated rats, compared with untreated controls, but was elevated nearly twofold in medium-dose-treated rats (p less than 0.05). The results indicate that time of cannabinoid administration as well as feeding pattern are critical in studies of the rat reproductive system.

Effects of cannabinoids given orally and reduced appetite on the male rat reproductive system.

Chronic oral treatment of young adult male Fischer rats with delta 9-tetrahydrocannabinol (THC), 1, 5 and 25 mg/kg/day, or crude marihuana extract (CME), 3, 15 and 75 mg/kg/day, suppresses growth of accessory sex organs and body weight gain in a dose-related manner. Animals pair fed with the THC (25 mg/kg) group gained slightly more in body weight than the THC group, but their relative accessory sex organ weights were intermediate between THC and ad libitum-fed control group weights. These latter differences may be due to altered serum androgen levels since these levels 2-6 h after last treatment were 0.15, 0.77 and 3.33 ng/ml for THC, pair-fed and ad libitum-fed groups, respectively. 24 h after the last treatment all groups were within normal levels. Thus, chronic cannabinoid treatment suppresses accessory sex organ weights and serum androgen levels greater than the suppression caused by reduced food intake alone.

Effect of cannabinoids on estrous cycle, ovulation and reproductive capacity of female A/J mice.

Virgin A/J female mice were intubated daily for 8 days (short term) or 70 days (long term) with 0, 1, 5, or 25 mg/kg delta 9-tetrahydrocannabinol (delta 9-THC) or 0, 3, 15, or 75 mg/kg crude marihuana extract (CME) in a sesame oil:polysorbate 80:saline vehicle. These dosages approximate light, moderate, and heavy human usage. Short-term exposure to CME has no significant effect on PMS-HCG-induced ovulation but appears to: (1) delay entry into proestrus at all dose levels; (2) depress serum progesterone during the luteal phase at the highest CME level used (75 mg/kg), and (3) inhibit female receptivity to males at least at the highest dosage. Long-term oral administration of CME or delta 9-thc had no significant effect on length of estrous cycles or mating (plug formation) but term pregnancies were reduced by 32 and 68% for medium and high dosages, respectively. After a 30-day recovery period, 80% of those females that failed to have successful pregnancies now became pregnant.

Effect of colchicine on estrogen action. I. Inhibition of 17 beta-estradiol-induced water and potassium uptake in the immature rat uterus.

The effects of colchicine on 17 beta-estradiol-induced water and electrolyte uptake in the uterus of the immature rat have been examined 6 h after treatment with this estrogen. Estradiol stimulates an increase in total uterine Na+, K+ and water while intracellular Na+ and K+ concentrations remain relatively unchanged. Assuming the sodium space is equivalent to the extracellular space, the extracellular fluid compartment increases about 84% in response to estradiol. Similarly, the intracellular compartment increases by about 62%. The uptake of water into the cellular compartment may be a direct response to a stimulation of K+ accumulation by uterine cells. Colchicine inhibits both estradiol-induced rise in intracellular potassium and both intra- and extracellular water.

Effect of colchicine on estrogen action. II. Translocation of 17 beta-estradiol cytosol receptor complex into the nucleus.

Colchicine has previously been shown in our laboratory to inhibit 17 beta-estradiol stimulation of uterine water uptake in the immature rat measured 6 h after administration of the agents. We sought to determine whether this effect was mediated through colchicine action on translocation of estradiol receptor complex into the uterine cell nucleus. The time course of estradiol effect on uterine water uptake was followed with and without concurrent colchicine administration up to 6 h after administration. At no time during this period did there appear to be any influence of colchicine on translocation of the estradiol receptor complex into the nucleus. Examination of physical chemical characteristics of the nuclear estradiol receptr complex after estradiol and estradiol plus colchicine treatments revealed no observable differences. Thus, colchicine inhibition of estradiol-stimulated uterine water retention does not appear to be mediated through inhibition of nuclear translocation of estradiol-receptor complex nor to be due to any reduced retention time of estradiol-receptor complex in uterine nuclei.

Uterine tubulin production during early pregnancy in the rabbit.

Rabbit uterine tubulin levels rise rapidly in the preimplantation period to peak values of about 10-fold in the endometrium and about 4-5 fold in the myometrium on days 3-5 of pregnancy. Endometrial tubulin falls to non-pregnancy levels by mid-pregnancy while myometrial tubulin declines much more slowly. The rise in tubulin exceeds the early rate of increase in total uterine protein and DNA. Following implantation, tubulin content of the decidual basal plate area increases rapidly to peak about day 12 then declines. Production of uterine tubulin appears capable of a major, short term response to gonadal hormone stimulation.

Translational control of specific uterine protein synthesis after estrogen induction.

The rate of leucine incorporation into a specific estrogen-induced protein of immature rat isolated by gel electrophoresis declines rapidly between 2-4 hr after estrogen stimulation in vivo followed by incubation in vitro. Actinomycin D present during the in vitro phase prevents this decline, and elicits a "superinduction" effect at 2 hr. Labeled induced protein remains stable during this time period, indicating that its decline is due to a reduction in synthesis capacity for the inducible protein, rather than to its degradation. A second injection of hormone at 3 hr has no effect on the reduced level of synthesis capacity for induced protein noted at 4 hr in the rat uterus.