Impaired gamete production and viability in Atlantic croaker collected throughout the 20,000 km(2) hypoxic region in the northern Gulf of Mexico.

The long-term impacts of recent marked increases in the incidence and extent of hypoxia (dissolved oxygen <2 mg/L) in coastal regions worldwide on fisheries and ecosystems are unknown. Reproductive impairment was investigated in Atlantic croaker collected in 2010 from the extensive coastal hypoxic region in the northern Gulf of Mexico. Potential fecundity was significantly lower in croaker collected throughout the ~20,000 km(2) hypoxic region than in croaker from normoxic sites.

Circulating levels of plasma IGF-I during recovery from size-selective harvesting in Menidia menidia.

Selection for growth-related traits in domesticated fishes often results in predictable changes within the growth hormone-insulin-like growth factor (GH-IGF-1) axis. Little is known about the mechanisms controlling changes in growth capacity resulting from fishery-induced evolution. We took advantage of a long-term study where Menidia menidia were selected for size at age over multiple generations to mimic fisheries-induced selection.

Cloning and characterization of leptin in a Perciform fish, the striped bass (Morone saxatilis): control of feeding and regulation by nutritional state.

In mammals, leptin is an anorexigenic peptide hormone that regulates energy homeostasis. It is produced predominantly by white adipose tissue and circulates as an endocrine indicator of energy reserves. Teleost leptin has been characterized in a few fish species, but its regulation is not well understood, particularly in response to nutritional status.

Dual role of IGF-II in oocyte maturation in southern flounder Paralichthys lethostigma: up-regulation of mPRα and resumption of meiosis.

Increasing evidence suggests a regulatory role for the IGF system in teleost oocyte maturation (OM). Our objectives were to determine if IGF-I and IGF-II regulate different stages of OM in southern flounder (Paralichthys lethostigma) and to identify the likely maturation-inducing steroid (MIS) in this species. The most abundant final product of ovarian steroidogenesis assays eluted at the position of 17,20β,21-trihydroxy-4-pregnen-3-one (20β-S).

Plasma ghrelin and growth hormone regulation in response to metabolic state in hybrid striped bass: effects of feeding, ghrelin and insulin-like growth factor-I on in vivo and in vitro GH secretion.

The regulation of growth hormone (GH) secretion by ghrelin during variable metabolic states is poorly understood. We examined plasma GH and ghrelin in hybrid striped bass (HSB) undergoing seasonally-based feeding and temperature manipulations. Fasting for 21 days (d) at 24 degrees C resulted in catabolism and up-regulation of plasma GH and ghrelin relative to fed controls.

Regulation of endocrine and paracrine sources of Igfs and Gh receptor during compensatory growth in hybrid striped bass (Morone chrysops X Morone saxatilis).

Compensatory growth (CG) is a period of growth acceleration that exceeds normal rates after animals are alleviated of certain growth-stunting conditions. In hybrid striped bass (HSB, Morone chrysops X Morone saxatilis), 3 weeks of complete feed restriction results in a catabolic state that, when relieved, renders a subsequent phase of CG. The catabolic state was characterized by depressed levels of hepatic Type I and II GH receptor (ghr1, ghr2) and igf1 mRNA, along with considerable decreases in plasma Igf1.

Discordant regulation of hepatic IGF-I mRNA and circulating IGF-I during compensatory growth in a teleost, the hybrid striped bass (Morone chrysopsxMorone saxatilis).

Compensatory growth (CG) is a period of growth that exceeds normal rates after animals are alleviated of certain growth-stunting conditions. Little is known, however, about the endocrine control of CG in teleosts. So, our aim was to induce CG in juvenile hybrid striped bass (HSB, Morone chrysopsxMorone saxatilis) through manipulations in feeding regimen, and then determine whether changes in circulating insulin-like growth factor-I (IGF-I) and hepatic IGF-I gene expression accompany the CG response.