library_construction_protocol: The pituitaries were isolated and washed four times with DPBS (Gibco, Waltham, MA, USA). Based on pituitary tissue morphology, we separated the anterior and posterior pituitary. The anterior pituitary was cleaned using DMEM and immediately cut into 2–3 mm tissue blocks using a scalpel. The tissue blocks were transferred into a centrifuge tube filled with type IV collagenase and placed in a 37℃ water bath for digestion. After filtering the cell suspension through a 40 µm cell strainer, the cells were cleaned with DMEM and collected into a centrifuge tube. Red blood cell lysis buffer was added at room temperature to resuspend cells and lyse the red blood cells for 2–5 min. Equal amounts of PBS-BSA (0.04%) solution were added to stop the lysis of red blood cells. The cells were then washed using PBS-BSA (0.04%) to obtain a single-cell suspension. The anterior pituitary was processed into a single-cell suspension, which was subjected to cell counting and viability assessments. Subsequently, the cells that met the quality inspection criteria were separated. The prepared single-cell suspension of the anterior pituitary was then divided into Gel Beads in Emulsions (GEMs) using an automated Chromium Controller, followed by the reverse transcription of mRNA into cDNA. Then, the cDNA was amplified and spliced. After library inspection, the cDNA was cyclized via PCR, whereas linear DNA molecules that were not cyclized were digested. Single-stranded circular DNA molecules were replicated via rolling cycle amplification, resulting in the generation of a DNA nanoball (DNB) containing multiple copies of DNA. DNBs of sufficient quality were then loaded onto patterned nanoarrays using the high-intensity DNA nanochip technique and sequenced through combinatorial Probe-Anchor Synthesis.