Effect of bafilomycin A1, a specific inhibitor of vacuolar (V-type) proton ATPases, on the capacitation of rabbit spermatozoa

Mammalian spermatozoa maintain precisely regulated ionic gradients that must be modified during capacitation and the acrosome reaction. In other cell types, ionic gradients are mainly regulated by the presence in plasma membranes of three metabolically different types of ATPases. The modifications induced during in vitro capacitation of rabbit spermatozoa by the specific inhibition of V-type H+-ATPases with bafilomycin A were studied. We used chlortetracycline binding to rabbit spermatozoa to monitor capacitation, and the coomassie brilliant blue method to identify acrosome-reacted sperm cells. There was a significant difference between the percentage of epididymal (66 +/- 7%) and ejaculated (43 +/- 11%) spermatozoa capacitated in vitro, after a 6-h incubation period in the presence of Ca2+ without ATPase inhibitor. The presence of bafilomycin significantly reduced these numbers (25 +/- 11 and 16+/- 8%, epididymal and ejaculated spermatozoa, respectively) and eliminated the difference. Ejaculated spermatozoa capacitated in the absence of bafilomycin showed a linear increase in the percentage of acrosome reactions induced by the addition of A23187 (12 +/- 5, 23+/- 6 and 31 +/- 5 after 15, 30 and 45 min). The presence of 0.2 micromol l-1 bafilomycin during the capacitation incubation induced a significant decrease in the acrosome reaction percentages (4 +/- 2, 8 +/- 3 and 14 +/- 4 after 15, 30 and 45 min). The addition of bafilomycin after the capacitating period had no effect upon the induction of the acrosome reaction by A23187. These results indicate that vacuolar ATPases play an important role during rabbit sperm capacitation. However, once the spermatozoa have been capacitated, V-type ATPases do not have a significant participation during the acrosome reaction.

Overexpression, purification, and characterization of glutaminase-interacting protein, a PDZ-domain protein from human brain

A human brain cDNA clone coding for a novel PDZ-domain protein of 124 amino acids has been previously isolated in our laboratory. The protein was termed GIP (glutaminase-interacting protein) because it interacts with the C-terminal region of the human brain glutaminase L. Here we report the heterologous expression of GIP as a histidine-tagged fusion protein in Escherichia coli cells. The induction conditions (temperature and isopropyl beta-d-thiogalactopyranoside concentrations) were optimized in such a way that GIP accounted for about 20% of the total E. coli protein. A simple and rapid procedure for purification was developed, which yielded 17 mg of purified GIP per liter of bacterial cell culture. The apparent molecular mass of the protein by SDS-PAGE was 16 kDa, whereas in native form it was determined to be 28 kDa, which suggests dimer formation. The nature and integrity of the recombinant protein were verified by mass spectrometry analysis. The functionality of the GIP protein was tested with an in vitro activity assay: after being pulled down with glutathione S-transferase-glutaminase, GIP was revealed by Western blot using anti-GIP antibodies. Furthermore, the glutaminase activity in crude rat liver extracts was inhibited by the presence of recombinant purified GIP protein.

Synthesis of a new 5'-O-triphosphate analog of 5-methyl 2'-O-deoxycytidine. Preliminary in vitro labelling for non-radioactive detection of DNA

We report the synthesis of the triphosphate of 5-methyl 4-N-[6-(p-bromobenzamido)hex-1-yl]-2'-O-deoxycytidine 3A. We also analyzed the formation of intramolecular H-bonds of 5-methyl 4-N-[n-[6-(p-bromobenzamido) caproyl amino]alk-1-yl]-2'-deoxycytidine compounds, and confirmed their presence by 1H-NMR studies. In vitro DNA labeling with modified nucleotides is preliminarily evaluated.

Mechanisms of blockade by the novel migraine prophylactic agent, dotarizine, of various brain and peripheral vessel contractility

The novel antimigraineur, dotarizine, inhibited 5-HT (5 hydroxytryptamine)-evoked contractions of rabbit vertebral, aorta, femoral and mesenteric arteries, with IC(50)s of 1.35, 1.40, 0.52 and 1.09 microM, respectively. Flunarizine had little effect on these contractions, while ketanserin was more potent (IC(50)s of 0.17 microM for vertebral, 0.22 microM for aorta, 0.05 microM for femoral and 0.03 microM for mesenteric arteries). At 10 microM, dotarizine caused 40% blockade of K(+)-evoked contractions of rabbit aorta, and 70% inhibition of 5-HT-evoked responses; these values were 30% and 20% for 10 microM flunarizine. Contractions of rabbit aorta elicited by noradrenaline, angiotensin II or prostaglandin F(2alpha) were not affected by 10 microM dotarizine or flunarizine. Ketanserin shifted to the right, in parallel, the concentration-response curves for 5-HT in rabbit aorta; however, dotarizine caused a non-competitive type of blockade, increasing the maximum 5-HT contraction at 30 nM and decreasing it at 3 and 30 microM. K(+)-evoked contractions of rabbit aorta were halved by 3 microM dotarizine in a voltage-independent manner; flunarizine caused a delayed-type, non-reversible post-drug blockade, and exhibited some voltage-dependence. Blockade by nifedipine was voltage-dependent and fully reversible. Ca(2+)-evoked contractions of depolarised bovine middle cerebral arteries were blocked by 1--3 microM dotarizine in a non-surmountable manner. Contraction of these vessels evoked by electrical stimulation was blocked 50% and 70% by 1 and 3 microM dotarizine, respectively. Dotarizine (1--3 microM) also inhibited to a similar extent the K(+)-evoked [(3)H]noradrenaline release from cultured rat sympathetic neurones. These data suggest that the mechanism of blockade by dotarizine of cerebral vessels contractility has three components: (i) presynaptic inhibition of noradrenaline release; (ii) blockade of postsynaptic vascular 5-HT receptors; (iii) blockade of Ca(2+)entry into the vascular smooth muscle cell cytosol. The compound does not affect the vascular receptors for noradrenaline, angiotensin II or prostaglandin F(2alpha).

Opposite effects of myocardial stretch and verapamil on the complexity of the ventricular fibrillatory pattern: an experimental study

An experimental model is used to analyze the effects of ventricular stretching and verapamil on the activation patterns during VF. Ten Langendorff-perfused rabbit hearts were used to record VF activity with an epicardial multiple electrode before, during, and after stretching with an intraventricular balloon, under both control conditions and during verapamil (Vp) infusion (0.4-0.8 mumol). The analyzed parameters were dominant frequency (FrD) spectral analysis, the median (MN) of the VF intervals, and the type of activation maps during VF (I = one wavelet without block lines, II = two simultaneous wavelets with block lines, III = three or more wavelets with block lines). Stretch accelerates VF (FrD: 22.8 +/- 6.4 vs 15.2 +/- 1.0 Hz, P < 0.01; MN: 48 +/- 13 vs 68 +/- 6 ms, P < 0.01). On fitting the FrD time changes to an exponential model after applying and suppressing stretch, the time constants (stretch: 101.2 +/- 19.6 s; stretch suppression: 97.8 +/- 33.2 s) do not differ significantly. Stretching induces a significant variation in the complexity of the VF activation maps with type III increments and type I and II decrements (control: I = 17.5%, II = 50.5%, III = 32%; stretch: I = 7%, II = 36.5%, III = 56.5%, P < 0.001). Vp accelerates VF (FrD: 20.9 +/- 1.9 Hz, P < 0.001 vs control; MN: 50 +/- 5 ms, P < 0.001 vs control) and diminishes activation maps complexity (I = 25.5%, II = 60.5%, III = 14%, P < 0.001 vs control). On applying stretch during Vp perfusion, the fibrillatory process is not accelerated to any greater degree. However, type I and II map decrements and type III increments are recorded, though reaching percentages similar to control (I = 16.5%, II = 53%, III = 30.5%, NS vs control). The following conclusions were found: (1) myocardial stretching accelerates VF and increases the complexity of the VF activation pattern; (2) time changes in the FrD of VF during and upon suppressing stretch fit an exponential model with similar time constants; and (3) although stretching and verapamil accelerate the VF process, they exert opposite effects upon the complexity of the fibrillatory pattern.

Sperm chromatin

Available data on dry and hydrated nuclear volume of mammalian spermatozoa indicate that available volume is clearly insufficient to contain sperm chromatin packed in nucleosome-like structures. Therefore, sperm DNA-protein complexes must be packed differently than somatic DNA-protein complexes. Packing of DNA in fixed, dehydrated mammalian sperm approaches the physical limits of molecular compaction, making mammalian sperm chromatin the most condensed eukaryotic DNA known. The fundamental packaging unit of sperm chromatin is a toroid approximately 900-A outer diameter. 200-A thickness, and 150-A diameter hole. Each toroid contains 60 kilobases of DNA and is linked to other toroids by uncoiled DNA stretches. The factors that contribute to mammalian chromatin structuration are still under study. The role of protamines in sperm chromatin condensation and nuclear shaping has been overstressed to the exclusion of other possible factors. Chromatin organization in sperm nuclei is maintained during sperm condensation by tight interactions with the nuclear matrix at fixed sites, inducing the formation of individual toroid-shaped DNA loop stuctures. Observations that abnormal manchettes affect sperm head shape and chromatin organization inducing sterility speak about manchette importance during chromatin organization. The presence in sperm chromatin of regions packaged in specific ways with several types of protamines or even with histones, indicates that nuclear shaping and chromatin organization must be under DNA control. The structural properties that distinguish sperm DNA from somatic DNA may play the most important role in chromatin organization.

Participation of DNA structure on sperm chromatin organization

The in vitro interaction between purified bovine liver and sperm DNA with somatic histones, to form nucleosomes, and with bovine and salmon protamines were studied. DNAse or microccocal nuclease digestion of liver DNA-histone reassociated chromatin produced the expected polynucleosome type of fragments. Electrophoretic patterns of digested sperm-DNA nucleosomes were different. Micrococcal nuclease digestion produced mainly fragments smaller than 100 bp and some nucleosome-type particles. Under DNAse activity most of the products were smaller than 100 bp, indicating an increased susceptibility of the sperm DNA-histone complexes to the hydrolytic activity of both nucleases, particularly toward DNAse I. This differential susceptibility was confirmed by sucrose gradient spectrophotometric analysis. Acridine orange (AO) staining of histone-DNA reassociated nucleosomes showed significant differences in fluorescence intensity, sperm DNA-histone complexes being almost twice as fluorescent as liver DNA-histone complexes. On the contrary, liver DNA/protamine complexes stained with AO were consistently more fluorescent than sperm DNA-protamine complexes. Finally, no differences in either fluorescence intensity or spectra were observed when liver and sperm DNA were stained with AO after interaction with salmon protamines. The data suggest that sperm DNA has important structural characteristics that differentiates it from somatic DNA. These differences seem to be species specific and must surely play an important role on the determination of the dramatic sequence of that participates sperm chromatin organization.

Study of ultrasonic contrast agents using a dual-frequency band technique

We have developed a dual-frequency band technique to study frequency-dependent phenomena associated with ultrasonic contrast agents. Our technique uses a superimposed high-frequency (10 MHz) broad-band ultrasound (US) pulse to investigate contrast agent interaction with a low-frequency (e.g., 0.5 MHz) ultrasonic field. Our digitally controlled system has the ability to produce two colinear, confocal US pulses at different center frequencies, to adjust the relative phasing and pulse repetition frequency of each pulse, and to acquire digital backscatter data. A series of experimental studies demonstrated that the high-frequency backscatter signal responded to several phenomena induced in contrast agent particles by the low-frequency beam. These phenomena included radial pulsations, nonlinear oscillations and depletion. Initial results also demonstrated a relative phase shift between the high- and low-frequency signals; this shift is due to a difference in sound velocity at these frequencies, and it may convey information about the contrast agent concentration.

Multiparametric study of atresia in ewe antral follicles: histology, flow cytometry, internucleosomal DNA fragmentation, and lysosomal enzyme activities in granulosa cells and follicular fluid

The differential quantitative participation of apoptosis and necrosis in ewe antral follicles of two different sizes, separated in four stages of atresia using macroscopic, histologic, and esteroid quantification methods was assessed. Annexin V binding and propidium iodide (PI) uptake was used to detect healthy live cells (Annexin V negative/PI negative), early apoptotic cells (Annexin V+/PI-), and necrotic or late apoptotic cells (PI+). Additionally we used internucleosomal DNA fragmentation as a quantitative estimate of apoptosis. Presence and distribution of lysosomal enzymes in follicular fluid and granulosa cells was used as a measure of necrotic cell death. DNA flow cytometry and gel electrophoresis were positively correlated with the progression of atresia, small atretic follicles tend to have higher percentages of internucleosomal cleaved DNA than follicles >6 mm. Annexin/PI binding also indicates that apoptosis and necrosis increase with atresia progression, generally apoptosis outweighs necrosis in small follicles. Acid phosphatase and glucosaminidase in follicular fluid of 3-6 mm follicles showed no significant modifications between healthy and initially atretic follicles, and only a small, but significant increase in activity in advancedly atretic follicles. On the contrary, lysosomal enzyme activity in follicles >6 mm showed positive correlation between atresia stages and the activities of acid phosphatase and glucosaminidase in follicular fluid. A similar size-differential behavior was found in free or membrane-bound lysosomal enzyme activity of granulosa cells. Necrosis, but principally apoptosis, were present during all stages of follicular maturation indicating that growth and maturation of ovarian follicles involves a continuous renewal of granulosa cells, regulated by apoptosis. Mechanisms regulating this equilibrium may participate in the final destiny, whether ovulation or atresia of ovarian follicles.

Coronary arteriovenous fistula with a giant aneurysm: role of transesophageal echocardiography

Congenital coronary arteriovenous fistulas are rare anomalies. Patients may present with congestive heart failure, ischemic chest pain, or endocarditis. In this case, transesophageal echocardiography provided valuable additional information to that obtained from cardiac catheterization, which was essential for the diagnosis and planning of surgical correction.

[Analysis of fatty acids from strains of Mycobacterium habana and Mycobacterium simiae]

A comparative analysis of mycobacterial fatty acid fractions of Mycobacteriun habana and Mycobacterium sineae strains was made. This study used the gas-liquid chromatography coupled with mass spectrometry. Chromatographic profiles obtained from this technique were exposed and compared. This technique proves to be valuable as an alternative element in mycobacterial characterization and makes it possible to analyze the possible differences that may exist among mycobacterial species and to identify the present fatty acid fractions. The outcome proved that the studied strains had quantifiable quantities of over 20 C atom chain fatty acids. There are small differences among the strains in terms of these organic components. It was confirmed that each of then describes a characteristic chromatographic pattern although the composition of present fatty acids is very similar in both studied species.

Synthesis of a new analog of thymidine for in vivo non-radioactive labeling of DNA

The introduction of 6-(p-bromobenzoylamino)caproyl radical in the methyl group of 2'-O-deoxythymidine is described. In vivo incorporation of this nucleoside to DNA was determined using a monoclonal antibody that recognized the radical.

A comparison of ultrasonic beams for thermal treatment of ocular tumors

OBJECTIVE

This study examined the relative merits of different ultrasonic beams and exposure modalities for treating ocular melanomas.

METHODS

Simulations were conducted to evaluate temperature patterns and lesion shapes induced by intense-ultrasound treatment of ocular tumors. In-vitro insonification experiments were conducted in bovine lenses.

RESULTS

Simulated hyperthermia exposures did not effectively treat tumor margins because of thermal conduction into nearby fluid-like media. Standard high-intensity focused beams produced narrow lesions during 2-s exposures. A high-intensity, multi-lobed beam, produced by a transducer with strip electrodes, generated asymmetric lesions with a single large dimension; this lesion shape could expedite the production of lesion matrices within large tumors. In-vitro cataract shapes were consistent with simulation results for focused high-intensity beams.

CONCLUSIONS

Thermal conduction and perfusion can cause underheating of tumor margins during hyperthermia unless special beam designs are used. The strip-electrode transducer configuration promises to expedite treatment of extended tumor volumes.

Changes in hypothalamic calmodulin concentration induced by perinatal hormone manipulation in the rat

Calmodulin (CaM) presence and concentration was determined (RIA) in the rat hypothalamus (2, 6, 12, 24 h and 90 days after birth) in vehicle-treated animal (controls), in testosterone propionate (TP)-treated females (30 microg/rat subcutaneously 1 h after birth) and in tamoxifen-treated males (200 microg/rat subcutaneously 1 h after birth). CaM concentration, either as total content/hypothalamus or as concentration per mg ww, was significantly higher in both male and female adult rats than in newborn subjects. CaM concentration/mg protein increased with age, being two times higher in adult males and greater than three times higher in adult females than in their respective newborns. Two, 12, and 24 h after birth CaM concentration was significantly lower in control females than in control males. This relation was reversed in adults in which CaM concentration was higher in females. The application of TP to the females and tamoxifen to the males, induced a significant decrease in CaM/mg protein, both in the newborn (2 and 6 h) and in the adult animals. In adults, treated females had CaM concentrations similar to those found in control males. Our data suggest: first, a lasting effect of newborn hormonal treatment upon the CaM concentration in rat hypothalamus; second, that CaM is preferentially synthesized in the adult female hypothalamus, indicating an important role of this protein in female reproductive function.

DNA unpacking in guinea pig sperm chromatin by heparin and reduced glutathione

The kinetics of nuclear decondensation and DNA unpacking induced by the action of a physiological concentration of heparin and glutathione of guinea pig spermatozoa was studied. Sperm (acrosomeless) suspensions were incubated at several different temperatures (37, 40, 43, and 46 degrees C), with a constant concentration of either heparin (50 microM) or reduced glutathione (12.5 mM) and increasing concentrations of the other reagent. Nuclei spermatozoa remained highly condensed when incubated in the medium alone or in either GSH or heparin alone for up to 72 h. Swelling of nuclei spermatozoa was initially observed during the first 20 min of incubation. The sperm nuclei initiate decompaction at the central part of the nuclear structure while at the periphery there remain numerous residues of densely packed chromatin. The swollen chromatin pattern presents the characteristic organization into "hub-like" nuclear bodies that measured 10-100 nm diameter joined by a network of chromatin fibers. At full nuclei decondensation chromatin end fibers are loose, probably meaning that DNA is not organized into loop domains. DNA presence was verified by the use of ethidium bromide and acridine orange.

[The male factor. I. Testicular function and gametogenesis]

The knowledge and treatment of human reproduction impairments have had an outstanding development during the last 15 years, mainly in topics related with infertility and sterility. Unfortunately in the area of male reproduction development has not been the same and despite the efforts accomplished, progress in the diagnosis and therapeutics of male infertility is limited. The functions of the male gonad are sperm production as well as the synthesis and secretion of steroid hormones, mainly testosterone. The efficient regulation of these functions depends on both the precise pituitary secretion of gonadotropic hormones and the endocrine, paracrine and autocrine responses of the testicular somatic cells to this stimulation. In this review we discuss the main events associated with the spermatogenic process, including the interactions among the testicular somatic cells and some characteristics of the physiological function of the hypothalamus-pituitary-testicle axis, as well as some pathophysiological states related to male infertility due to "pretesticular causes".

[The male factor. II. Spermatozoa. Structure and function]

In the "male factor" entity, the structural and functional correlation determining the sperm fertilizing capacity is constituted by a group of cellular factors that must be evaluated in the semen of the infertile men. Structurally the spermatozoa of the head, the middle piece and the flagellum. The head has a highly condensed haploid nucleus, surrounded by a thin layer of cytoplasmic material, which is covered in a cap-like fashion by the membrane limiting the acrosome. This last organelle, which has characteristics similar to those of a secretory granule, secretes in a programmed way the hydrolytic enzymes that facilitate the fertilization process. The middle piece contains the mitocondrail sheet, responsible for the energy metabolism of the sperm cell. The flagellum has the same basic structure of other cilia or flagella, but also has particular characteristics due to the presence of the outer dense fibers and the fibrous sheath. In the semen analysis from infertile men the abnormalities most frequently observed belong to the number, morphology, variability, motility of capacitation-acrosome reaction of the sperm cells. However, due to the apparent multifactorial etiology of the male factor, now a days we only have few options for medical or pharmacological treatment. In this paper we review the morphology and ultrastructure considered as "normal" in the human spermatozoa, as well as we describe the most frequent alterations in these parameters. At the same time, we discuss the impact of sperm motility and of the capacitation-acrosome reaction process in male fertility.

[The male factor. III. Importance, diagnosis and perspectives]

According to the World Health Organization, the male factor is present in 40-50% of infertile couples, therefore the importance of the continuity in multidisciplinary studies related to understand the mechanisms regulation the male reproductive process. Semen analysis is still almost the only instrument for the study of men with disruptions in their fertility. However, the main problem to establish a diagnosis with predictive value for male infertility, is the fact that the morphological and/or functional characteristics of the male gamete that determine its fertilizing capacity are still in the process of validation. Even more, the correlations among semen characteristics and bioactive hormones concentrations in serum, and the individual fertility potential have not been established either. In this context, we discuss here some topics that we considered of great importance in relation to male fertility diagnosis, i.e. the main causes of infertility, the advances in the recognition of the morpho-functional correlation that determines the fertilizing capacity of the male gamete and the criteria that prevail in the laboratory to proper handle and evaluate the semen samples.

[Male pseudohermaphroditism caused by enzymatic deficiency of 17-alpha-hydroxylase. 1st case reported in Puerto Rico]

A 36 year old white female came to our service after having been evaluated on repetitive occasions in the past for a workup of gigantism and acromegalic features. Since childhood she had developed tall stature, frontal bossing, prominence of zygomatic bones, separated teeth, large hands and size 14 shoes. Human growth hormone and somatomedin serum levels had been normal on all occasions tested. Her past history was significant for primary amenorrhea and a 12 year history of hypertension. On physical examination BP was 140/100, height 6' 2", weight 2571 bs. Her phenotype was truly acromegalic. There was absence of axillary and pubic hair with no breast development. External genitalia was of female appearance. Laboratory evaluation showed increased FSH of 88 mlU/ml, increase LH of 65.6 mlU/ml and decreased E2 of 12.6 pg/ml. Other findings were low serum cortisol of 0.2 mg/dl, high ACTH of 344 pg/ml, low 17-Ketosteroids, high pregnenolone levels of 595 mg/dl, low 17-hydroxypregnenolone less than 10 ng/dl, very high aldosterone of 31 ng/dl and suppressed PRA of less than 0.1 ng/ml. A pelvic sonogram showed a right ovoid structure which could represent a gonad and failed to identify the uterus and left gonad. A bone densitometry showed a decrease bone mineral density compatible with osteoporosis. Chromosome study showed a karyotype of 46-XY. A diagnosis was made of congenital adrenal hyperplasia secondary to 17-alpha-hydroxylase deficiency in a genotypic male. Our patient was referred to the department of gynecology for surgical removal of the gonads. It is amazing how a patient with severe adrenal insufficiency can withstand 36 years of her life undiagnosed without going into an adrenal crisis. Her tall stature and acromegalic features were the striking signs confusing all physicians and delaying the correct diagnosis and appropriate treatment. There has been reported worldwide, nearly 120 cases with documented severe 17-alpha-hydroxylase deficiency. To our knowledge this is the first case identified in Puerto Rico of male pseudohermaphroditism secondary to 17-alpha-hydroxylase enzyme deficiency.

C, Tarragó-C. MR, Rosado A. Supplementation with chromium picolinate reduces the incidence of placental retention in dairy cows

A test with two groups (n for each group = 25) of Holstein cows was conducted to evaluate the effects of chromium picolinate (CrPic) on the incidence of placenta retention (PR). Organic chromium supplementation, equivalent to 3.5 mg Cr d−1 per cow, administered during the last 9 wk of pregnancy, decreased nearly four times the incidence of placental retention observed in unsupplemented cows (16% vs. 56%, P < 0.05, chi square test). Calf body weight (BW) at birth was similar in both groups (without Cr = 43.92 ± 0.75 kg vs. Cr supplementation = 44.26 ± 0.84 kg). Key words: Placental retention, chromium picolinate, stress, dairy cows

Metalloproteinase activity during growth, maturation and atresia in the ovarian follicles of the goat

Metalloproteinases are an important group of hydrolytic enzymes which participate in interstitial matrix degradation during tissue remodelling processes and therefore may be required during follicular growth and maturation. The activity of metalloproteinases (collagenases, gelatinase, and Pz-peptidase), was measured during growth, maturation and atresia of goat antral follicles. These follicles (n = 67) were separated by size and also classified into four groups: non-atretic (Group I); early atretic (Stage I) (Group II); moderately atretic (Stage II) (Group IIIa); and, late atretic (Stage III) (Group IIIb). Pz-peptidase was greater in granulosa than in thecal cells, and almost absent in follicular fluid. In non-atretic follicles, activity in granulosa cells increased with increasing follicle size, whereas activity peaked in 3-6 mm follicles in thecal cells. Atresia was associated with declining activity in thecal cells from follicles in the 3-6 mm range and in granulosa cells from the > 6 mm range. Interstitial collagenase activity was significant and similar in granulosa and thecal cell extracts and low in follicular fluid from non-atretic follicles. Activity increased significantly in thecal cells, but decreased significantly in granulosa cells from large (> 6 mm) non-atretic follicles. Atresia was associated with declining activity in both types cells and increasing activity in follicular fluid. Gelatinase activity was some times associated with five regions corresponding to molecular weights of 22.1, 30.7, 39.6, 63.8 and 71.4 kDa, and rarely at 91.3 and 81.2 kDa. Overall activity declined with atresia in thecal cells from follicles in the 3-6 mm range, but not in those > 6 mm. In granulosa cells from follicles 3-6 mm, activity varied widely with stage of atresia, while in cells from follicles > 6 mm, activity was greatly increased in atretic follicles.